Comments

I just look to Andeas Melzer website and saw the values presented for the spores of the species under consideration:C. stercorea: 6-8,7 x (3-) 4,5-5 µm,C. trispora: 6,5-10,5 (-11,5) x (4,5-) 6-7 µm.
This reinforce my conviction that the species of my specimens is C. stercorea.

Using the key for the genus Coprinus in Flora Agaricina Neerlandica (online version available at http://www.grzyby.pl/...), which include at the time it was published also Coprinellus, Coprinopsis and Parasola, due to the features of this specimens we are directly conduced to Subsect. Narcotici and here we have only a few species with very small specimens and capable of growing on dung, namely:Coprinus foetidellus [it remains with this name at Index Fungorum],Coprinus stercoreus (= Coprinopsis stercorea),Coprinus trisporus (= Coprinopsis trispora),Coprinus tuberosus (= Coprinopsis tuberosa).
Of these Coprinopsis stercorea is the smaller and has a pure white veil when young, the others having from the start pinkish-grey, pale-grey or mouse grey veil. C. tuberosa has as distinguish feature a dark-brown/black sclerotium at the base. All of them have a veil consisting of more or less globose cells covered with nipple-shaped warts, but the spores have different dimensions, respectively:
- 7.5-11.0 × 4.5-7.0 µm (Qav=1.5-1.6);
- 5.5-7.5 × 3.0-4.0 µm (Qav=1.65-1.8);
- 6.5-9.0 × 4.5-5.5 µm (Qav=1.4-1.6);
- 8.0-11.0 × 5.0-6.5 µm (Qav=1.65),
where Qav is the average value of Q=Lenght/Breath=L/B and the dimensions are given as L x B.
Here are some data from the microcopic observation of my specimens:
- Spores (here the second dimension refers to the Width):
(5.8) 6.4-7.8 (8.1) x (3.5)3.6 – 4.1(4.5) µm
Q = (1.5) 1.7 – 2 (2.3) ; N = 36
Me = 7.2 × 3.9 µm ; Qe = 1.8;
- Cheilocystidia: some of the bigger measured with 35.9-39.1 × 24.1-25.6 µm (N = 6)
- Cells from the veil: some of the bigger measured with 42.4-55.2 × 35.3-52.2 µm (N=11).
Taking into account all the factors, mainly the dimension and colours of the specimens and the dimension of the spores, I think that the most probable classification is C. stercorea, though the widht of the spores is a bit to large. On the other hand, the lenght of the spores rule out C. foetidella and C. tuberosa, the absence of the sclerotia at the base is another reason to exclude the latter. I also think that it could also be C. trisporus, but the habitat of this species is restricted to dung of cow and horse, which I’m sure it is not the case.